Numerous applications for chip cards are known in the art. For example, a cash card or other so-called "electronic money" is known for shopping or for using services. It is possible to select from two possibilities: Prepaid "Debit Cards" wherefrom a certain value is directly deducted when it is used, and "Credit Cards" wherein the name of the bank and the owner's credit limit are stored. The amount will be deducted from a linked account when the card is used. With prepaid cards, e.g. with telephone cards, the respective amount is debited to the purchaser's card and credited to the dealer's card. The dealer can then go to his/her bank and have this amount credited to his/her bank account. Additional applications are so-called loading machines where the amount remaining on the chip card can be increased by payment of cash. An application therefor is, for example, chip cards for cafeteria lunches, beverages and food vending machines. In this case for example, a prepaid amount is credited to the card and this amount is subsequently decreased, like with a telephone card, or the amount will be deducted directly from the paycheck (from: "Der Mikrorechner in der Brieftasche", bei Chip-Karten hat Europa die Nase vorn ("The microcomputer in the wallet", Europe is in first place with chip cards, Part 1, by: Helmuth Lamme, Elektronik 20/1993). The aforedescribed conventional chip cards require that a backward channel is provided for the debit process. This backward channel is used to debit the card immediately or to make a note that a debit has occurred.